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Biomedical subjects

J D Cohn

Publications and source records attributed to J D Cohn.

17 recordsLinked to original sources
PubMed1979

Delayed pacemaker erosion due to electrode seal defects.

Over a 7-year period, follow-up data were available on 163 patients who underwent 209 pacemaker-related operations for initial insertion or revision of previously implanted units. During the follow-up period, 16 pacemaker generator units were remoaved from 16 pacemaker generator units were removed from 12 patients solely because of the development of local skin erosion. This represents a 7.7% incidence of pacemaker generator erosion. Tree units were removed within a 3-month interval following pacemaker implantation and were associated with positive bacterial cultures, theraby indicating an infectious cause. Findings at removal of the remaining 13 pacemaker generators included extensive fibrosis with chronic inflammation, fibroblastic proliferation, and granulation tissue, which was most prominent at the site of insertion of the pacemaker lead into the pacemaker generator unit. Granulation tissue frequently led from this area to the area of skin attenuation and erythema. Inspection of the pacemaker generator units and electrodes demonstrated fluid ingress and tissue ingrowth toward the electrode due to inadequate seal mechanisms. Inadequate seal design of the pacemaker generator and electrode junction leads to tissue ingrowth with fibroblastic proliferatiog chronic inflammation, and eventual pacemaker erosion.

Aged↗
PubMed1979

Shunt effect of carboxyhemoglobin.

Estimation of intrapulmonary blood shunt fraction requires accurate evaluation of pulmonary capillary, arterial, and mixed venous oxygen contents. The presence of carboxyhemoglobin, as well as methemoglobin and sulfhemoglobin, may lead to large errors in the calculated intrapulmonary blood shunt fraction. The errors are most pronounced at low values of carboxyhemoglobin and low values of true intrapulmonary shunt fraction.

Carboxyhemoglobin↗
PubMed1978

Documentation of vasomotor dysfunction by indicator dilution curve analysis.

Indocyanine green dye dilution curves with abnormal contours have been recorded in four patients with acute and critical illnesses using standardized recording methods. The abnormal curves are characterized by a high and prolonged concentration of dye occurring after the peak concentration. This altered contour can be detected by use of routine mathematical processing since the derived hemodynamic parameters are affected by the altered contour. A physiologic basis for the altered curve contour is proposed.

Acute Disease↗
PubMed1978

A shunt equation for estimating the splenic component of portal hypertension.

A modification of the Berggren pulmonary shunt equation was derived for use in estimating the splenic component of portal hypertension. It was used in nine patients, six of whom had sufficient decreases in portal flow and pressure after splenic artery and coronary vein ligation. The average decrease in portal flow was 52%.

Adult↗
PubMed1977

Physiologic profiles in circulatory support and management of the critically ill.

An automated system has been developed for measuring hemodynamic, oxygen transport and tissue utilization functions. Rapid measurement and data analysis of physiologic profiles by paramedical personnel allow prompt evaluation of altered cardiovascular function. Evaluation of physiologic function allows therapeutic interventions to be instituted on a timely basis, appropriately directed toward improvement of the measured cardiovascular abnormalities. Physiologic profile studies were performed on 1016 occasions in 580 patients during a three-year period and form the basis of this report. Although utilized on hospitalized patients, there are implications for use in evaluating and treating all critically ill patients.

Biological Transport, Active↗
PubMed1976

Sternal wire closure by an instrumental method.

Effective median sternotomy closure requires approximation of the sterum under appropriate tension in an expeditious manner. An instrument has been developed to provide tightening of applied sternal wires, allowing proper tension to be established. After tightening, the twisted wire is automatically trimmed by the instrument. The ease and reproducibility of this wire closure technic has allowed the method to be performed on a routine basis.

Stainless Steel↗
PubMedDate not supplied

The automated physiologic profile.

The automated physiologic profile provides the critical care physician with hemodynamic, oxygen consumption and tissue utilization data at reasonable cost. A paramedical assistant performs all data acquisition, recordings and blood sampling procedures. Data reduction is performed through use of off-the-shelf desk-top calculator equipment and accessories and a standardized graphic display is provided for the physician in charge. The physiologic profile has been utilized in high-risk patients requiring medical and surgical interventions. It is routinely employed in postoperative monitoring of cardiac patients and patients undergoing major surgical procedures with associated cardiovascular decompensation. Diagnosis of cardiac and pulmonary deterioration and promptness of advanced support interventions represent additional areas of effective clinical application.

Cardiovascular Diseases↗
PubMedDate not supplied

Persistent left superior vena cava complicating hemodynamic monitoring catheterization.

Two cases of flow-directed, balloon-tipped catheterizations of the right heart via a persistent left superior vena cava are presented. In both cases, the monitoring catheters assumed similar, atypical configurations on plain chest roentgenograms. Recognition of the characteristic configuration of the course of transvenous catheters through the persistent left superior vena cava allows for plain film diagnosis of this anomaly.

Adult↗
PubMedDate not supplied

Gamma-ray densitometry in the analysis of hemodynamic function.

An instrument has been developed to record contrast dilution curves by a noninvasive technique. Transthoracic roentgen density alterations are recorded by use of a solid state radiation detector array. A small amount of injected nonradioactive, radiopaque contrast material is distrubuted throughout the central circulation. The detector array positioned over the cardiopulmonary silhouette, records changes in density during the passage of the contrast material, and typical indicator dilution curves are transcribed. These curves reflect changes in blood flow distribution, vascular volume, cardiac function, and intrathoracic vascular shunts; and define the hemodynamic status of the circulatory system.

Absorptiometry, Photon↗
PubMedDate not supplied

A fully automated cardiac output analysis system.

An automatic cardiac output analysis system is described in which indicator dilution studies are performed serially without operator assistance. Indicator dye injection, blood sampling, and monitoring for air entry into the system are performed automatically through a present program sequence. Sampled blood is returned to the subject through a venous cannula resulting in an absence of blood loss. This system may be used in performing cardiac output analyses on a serial basis and in infants and small animals where blood loss is critical.

Automation↗
PubMedDate not supplied

A cost-effective system for obtaining comprehensive cardiovascular information on the critically ill patient.

A relatively simple and inexpensive data management system is described with which comprehensive physiologic and cardiovascular profiles are produced. The system is comprised of a desk-top programmable calculator interfaced with an acoustic digitizer input, and an X-Y plotter, with alphanumeric printing output capability. Numerical clinical data such as intracardiac pressures and blood gas values are entered into the calculator via the keyboard, and graphical data such as dye-dilution curves or ventricular contours are digitized with a pen stylus on the acoustic tablet. The data are processed in the calculator and the results charted in familiar and readily interpreted bar-graph format on preprinted charts on the X-Y plotter. The entire system is inexpensive and compact enough to be applicable to small- and medium-size community hospitals.

Cardiovascular Physiological Phenomena↗
PubMedDate not supplied

Physiologic profiles in circulatory support.

Measurements of hemodynamic, oxygen transport, and tissue utilization functions were incorporated into a physiologic profile assessment system in order to evaluate patients who are candidates for mechanical support of the failing heart. Circulatory function was assessed in patients with acute myocardial infarction associated with diminished peripheral perfusion and compared to an age-matched, normal patient group. Serial studies performed prior to and during intra-aortic balloon counterpulsation provide a means to assess circulatory status accurately and document the efficacy of therapeutic interventions.

Acute Disease↗